Axially collapsible steering columns with energy absorbing support members are used throughout the automobile industry to reduce high energy impact forces of a steering wheel. Most commonly, these support members are transversely disposed of the steering column, and surround the steering column at their center, and include plastically deformable flanges extending transversely of the steering column and anchored at the outboard end of the flange to the dash or instrument panel supporting frame work of the vehicle. Examples of these support members are disclosed in U.S. Pat. Nos. 4,194,411 and 4,627,306.
The support of the steering column may be limited to one such support member, or may include the same type of support member at both the forward and rear positions on the steering column as shown in U.S. Pat. No. 3,505,897.
Such support members have several common characteristics. First, only discrete portions in the energy absorbing sections of these support members contribute to energy absorption, which makes it difficult to provide uniform energy absorption over the full design displacement of the steering column.
Second, these support members tend to be oversized since major portions of the part are not utilized for energy absorption.
Third, these support members generally require attachment to the vehicle on both sides of the steering column or from the top thereof, which unnecessarily complicates the vehicle interior design and makes more difficult the production installation of the steering column assembly.
Finally, these support members provide little design selectivity in determining mode or path of collapse of the steering column.